(1) Field of the Invention
The present invention generally relates to a method and an apparatus for analyzing a drivetrain assembly and more particularly, to a method and an apparatus for accurately communicating desired types of signals to the drivetrain assembly which may be used to conduct a torsional modal analysis of the drivetrain assembly.
(2) Background of the Invention
It is desirable to determine the torsional modes of a drivetrain assembly in order to determine the manner in which the drivetrain assembly operates or behaves in actual operation and to evaluate various drivetrain design configurations. Particularly, in such an analysis, several pseudo-randomly generated signals of a certain pseudo-randomly generated frequency and a substantially similar amplitude are generated and communicated to the drivetrain assembly, and the torsional behavior of the drivetrain assembly, upon receipt of these signals, is noted and analyzed. Particularly, certain torsional characteristics or attributes of the drivetrain assembly, for certain signal frequencies, are noted and these torsional characteristics, such as damping, cooperatively form a torsional modal signature for the drivetrain assembly which allows a designer to discern certain operating attributes or characteristics of the drivetrain assembly.
While the foregoing strategy does allow some torsional modal analysis to be made of the drivetrain assembly, it suffers from some drawbacks. For example, the characteristics of the signals (e.g., the frequency and/or the amplitude of the signals) change as the signals are communicated to the drivetrain assembly due to resonance or other dynamic type attributes of the member/apparatus which couples the signals to the drivetrain assembly, thereby causing the analysis to become errant since the observed drivetrain behavior is not the result of the signal frequency and amplitude which was originally generated or desired/programmed, but is the result of a signal having a new and often unknown frequency and amplitude. The amount of such error is often unknown and may cause a drivetrain assembly to be produced having undesired and relatively unknown behavioral characteristics. The present invention overcomes these drawbacks in a new and novel manner and allows the behavior of a drivetrain assembly to be accurately determined.
It is a first non-limiting advantage of the present invention to provide a method and an apparatus for analyzing a drivetrain assembly which overcomes some or all of the previously delineated drawbacks associated with prior methods and apparatuses.
It is a second non-limiting advantage of the present invention to provide a method and an apparatus for analyzing a drivetrain assembly which overcomes some or all of the previously delineated drawbacks associated with prior methods and apparatuses and which, by way of example and without limitation, allows a torsional modal analysis to be accurately and efficiently made of a drivetrain assembly.
It is third non-limiting advantage of the present invention to provide a method and an apparatus for analyzing a drivetrain assembly which overcomes some or all of the previously delineated drawbacks associated with prior methods and apparatuses and which, by way of example and without limitation, uses an error feedback strategy to increase the accuracy of the overall analysis.
According to a first non-limiting aspect of the present invention, an assembly for testing a certain apparatus is provided. The assembly comprises a first apparatus which generates at least one signal by use of a certain error measurement and which communicates the at least one signal to the certain apparatus; and a second apparatus which is coupled to the certain apparatus and which measures a certain attribute of the certain apparatus after the at least one signal has been communicated to the current apparatus.
According to a second non-limiting aspect of the present invention, an assembly for conducting a torsional mode analysis upon a portion of a vehicle is provided. The assembly comprises a generator assembly which selectively and pseudo-randomly generates a first signal and which generates a second signal by use of a certain error measurement; an excitor assembly coupled to the portion of the vehicle, which receives the first signal, which uses the received first signal to generate a third signal, and which communicates the third signal to the portion of the vehicle to excite the portion of said vehicle, wherein, the excitor assembly creates said error measurement by use of said first and third signals, the excitor assembly further receiving the second signal, using the second signal in combination with the error measurement to produce a fourth signal, and communicating the fourth signal to the portion of the vehicle to excite the portion of the vehicle; and a torsional mode analysis apparatus which is coupled to the portion of said vehicle and which identifies a torsional mode of the portion of the vehicle as the portion of the vehicle is excited by the third and fourth signals.
According to a third non-limiting aspect of the present invention, a method for determining the behavior of a drivetrain is provided. The method comprises the steps of: generating a first signal; using the first signal to generate a second signal; exciting the drivetrain by the use of the second signal; measuring a certain attribute of the drivetrain as the drivetrain is excited by the second signal; creating an error value by use of the first and second signals; using the error value to generate a third signal; using the third signal to generate a fourth signal; exciting the drivetrain by use of the fourth signal; and measuring the certain attribute of the drivetrain as the drivetrain is excited by the fourth signal.
These and other features, aspects, and advantages of the present invention will become apparent from a reading of the following detailed description of the preferred embodiment invention and by reference to the following drawings.